Polyunsaturated fatty acids are defined as fatty acids which have a plurality of carbon-carbon double bonds on the molecule, and are classified according to the positions of the double bonds as, for example, ω-3 polyunsaturated fatty acids or ω-6 polyunsaturated fatty acids. Examples of ω-3 polyunsaturated fatty acids include α-linolenic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Examples of ω-6 polyunsaturated fatty acids include linoleic acid, γ-linolenic acid and arachidonic acid. Because polyunsaturated fatty acids exhibit a variety of effects, such as antiatherogenic effects, platelet aggregation-inhibiting effects, blood lipid-lowering effects, anti-inflammatory effects, anticancer effects and central nervous system effects, they are formulated in various types of food products and are also sold commercially as health foods or pharmaceutical products. Polyunsaturated fatty acids readily oxidize. Because they emit a characteristic odor when they oxidize, such fatty acids are generally prepared in capsule form to prevent oxidation and block odors. For polyunsaturated fatty acids to exhibit effects such as those mentioned above, they must be taken in a dose of from several hundred milligrams to several grams at a time. Not only are the capsules large and difficult to swallow, a plurality of capsules must be ingested. These and other problems pose a challenge to the administration of polyunsaturated fatty acids. Such problems are particularly acute in the elderly and other patients who have difficulty swallowing. Moreover, in patients whose intake of water is restricted, large and/or numerous capsules must be ingested with a limited amount of water, which is highly unpleasant.
Also, in the elderly and other patients who have difficulty swallowing, it is not uncommon for food and drink to enter the trachea due to aspiration, causing pneumonia. Such aspiration is known to occur less readily with high-viscosity gels and jellies than with low-viscosity liquids such as water (Kuchi kara taberu enka-shōgai Q&A [Swallowing disorders when eating by mouth: Questions and Answers], by Ichiro FUJISHIMA (Chuohoki Publishers)). This has led recently to the development and marketing of jelly preparations as pharmaceuticals which can easily be taken even by patients having a lowered ability to swallow.
Prior-art jelly preparations include such marketed jelly preparations as Acivir Oral Jelly (manufactured by Ohta Pharmaceutical Co., Ltd./sold by Nikken Chemicals Co., Ltd.) which contains the antiviral agent aciclovir, Ciloslet Oral Jelly (manufactured by Ohta Pharmaceutical Co., Ltd./sold by Zeria Pharmaceutical Co., Ltd.) which contains the drug cilostazol used for treating chronic arterial occlusion, and Pabron Cough Medicine, an over-the-counter medication in stick jelly form (manufactured by Ohta Pharmaceutical Co., Ltd./sold by Taisho Pharmaceutical Co., Ltd.).
In addition, jelly compositions containing carrageenan, locust bean gum and polyacrylic acid which do not readily undergo syneresis and have an excellent storage stability (e.g., Patent Documents 1 and 2), and jelly-like compositions which are formulated with undiluted Chinese herbal medications, contain carrageenan, locust bean gum, xanthan gum and phosphate buffers, and have an excellent storage stability (e.g., Patent Document 3) have been disclosed.
Fatty acid-containing jelly-like compositions that have been disclosed include jelly-like candies composed of γ-linolenic acid-containing oils, gelling agents, water and sugars (e.g., Patent Document 4); jelly foods which contain at least powdered konjak and a gelling agent, additionally include 0.5 to 10.0 wt % of fats and oils, and have a smooth, tofu-like consistency with good mouth-melt characteristics (e.g., Patent Document 5); retort foods of fish and shellfish in which the seasoning broth contains κ-carrageenan and locust bean gum and has been jellied (e.g., Patent Document 6); and gel-like foods composed primarily of 1 to 10 wt % of medium-chain fatty acids, retarded blood sugar value delay-elevating carbohydrates, gelling agents and water (e.g., Patent Document 7).
However, in the prior art on these jelly-like compositions and jelly-like food products, no mention can be found of any investigations, disclosures or suggestions concerning the inclusion of polyunsaturated fatty acids in an amount greater than 10 wt % and the disintegrating ability, releasability and biological utility which are critical to pharmaceutical compositions. More specifically, in the prior art on such jelly compositions, no disclosure whatsoever is made concerning art relating to the release of oils and fats from such jelly compositions within the oral cavity or the digestive tract following administration, which is of particular importance for pharmaceutical compositions. Nor has any art been investigated based on a desire to increase the in vivo absorptivity of unsaturated fatty acids as active ingredients.
Moreover, to ingest at one time the 600 mg of EPA that is generally regarded as exhibiting a physiological effect by taking a jelly having an oil and fat content of 2 wt % according to the art described in Patent Document 5, for example, one would have to take about 30 g of the jelly. As noted above, in order for the polyunsaturated fatty acids to be efficiently absorbed in vivo, the jelly must be taken after a meal. However, in a patient who feels full after a meal, the requirement that a large amount of jelly be ingested will effectively lower compliance, preventing the required amount from being ingested. Furthermore, in elderly and other patients having a diminished ability to swallow and in patients whose intake of water is restricted, administration may be difficult if the amount of jelly that must be ingested to receive the effective dose of the active ingredient is large.    Patent Document 1: JP 9-187233 A    Patent Document 2: JP 9-194346 A    Patent Document 3: JP 2001-114696 A    Patent Document 4: JP 9-224578 A    Patent Document 5: JP 2002-354991 A    Patent Document 6: JP 2001-275620 A    Patent Document 7: JP 2004-8165 A